The sharp rise prompted the Swiss National Bank to step in Wednesday to try and cool the rally.

The Zurich-based bank bank cut interest rates to "as close to zero as possible" and said it plans to boost the supply of Swiss francs to money markets this week.

The bank said it considers the franc to be "massively overvalued," and that its strength "is threatening the development of the economy and increasing the downside risks to price stability in Switzerland."

The announcement appeared to have the desired effect, with the Swiss franc losing some ground against the euro and dollar for the first time in a week.

"The surprise move suggests that we will see the Swiss National Bank intervene in the currency market to balance the risks for the region, but the central bank may struggle to stem the bullish sentiment underlying the franc as investors look for an alternative to the U.S. dollar," said David Song, currency analyst at the DailyFX.

"Overall, the Swiss franc's strength has been the symbol of significant debt imbalances between major economies," Komileva said. "Given that deleveraging across the United States, United Kingdom and parts of the eurozone has much further to run and global financial fragility is unlikely to disappear, this remains a structurally positive environment for the Swiss franc."